The commen denominator for 10 and 2 would be 10. so 3/10 will stay the same ... and now we change the 1/2 to a fraction that has its denominator as 10. so the new fractions would be ... 3/10, and 5/10.
1-2. The best estimate for the population mean would be sample mean of 60 gallons. Since we know that the sample mean is the best point of estimate. Since sample size n=16 is less than 25, we use the t distribution. Assume population from normal distribution.
3. Given a=0.1, the t (0.05, df = n – 1 = 15)=1.75
4. xbar ± t*s/vn = 60 ± 1.75*20/4 = ( 51.25, 68.75)
5. Since the interval include 63, it is reasonable.
M<7 + m<8 + m<9 = m<EAD
31 + 22 + m<9 = 102
53 + m<9 = 102
m<9 = 49
